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photoreception and single-chambered eyes

Pinhole eyes, in which the size of the pigment aperture is reduced, have better resolution than pigment cup eyes. The most impressive
pinhole eyes are found in the mollusk genus
Nautilus, a member of a cephalopod group that has changed little since the Cambrian Period (about 542 million to 488 million years ago). These organisms have eyes that are large, about...